The Non-Equilibrium Solidification Microstructure And Process Of Al-3Fe Alloy By Slow Cooling

Under noremal solidification conditions,there are coarse plate-like Al3Fe phases in Al-Fe alloy due to the limited solid solubility of Fe,which affects the strength and application of the alloy.In order to improve the distribution of Fe-rich phase,the solidification process of Al-3Fe alloy under slowly cooling in curcible and metal mould with different mould temperature and pouring temperature was studied in this work.The solidified microstructures and cooling curves were obtained.The influence of mould temperature and pouring temperature on solidification microstructure and cooling curves of Al-3Fe alloy were analyzed.The results are as following:(1)Al-3Fe alloy slowly cooled in the crucible near the equilibrium solidification consists of coarse plate-like Al3Fe phase and Al-Al3Fe eutectic structure.Non-equilibrium solidification occurs during cast-iron mould casting which is in pseudo-eutectic region and the microstructure of Al-3Fe alloy is Al-Al6Fe eutectic.(2)The primary ?-Al dendrite appears at the edge of Al-3Fe alloy ingot during solidified in the cast-iron mould.With the mould temperature increasing,the range of the?-Al dendrite decreases at certain pouring temperature.The eutectic reaction time becomes shorter at the edge and center region of ingot.(3)With the increasing of pouring temperature,the range of the ?-Al dendrite increasing when temperature of mould is 15?.Also eutectic reaction time becomes shorter at the edge of ingot and center region.Primary Al3Fe with surrounding dendritic halos gradually reduce as the increasing mould temperature.(4)When Al-3Fe alloy solidified in the cast-iron mould at mould temperature of 50?and pouring temperature of 810?,eutectic temperature of Al-Al6Fe is 643.83? at the center of ingot and havelittle effect on primary Al3Fe with surrounding dendritic halos.